Replace the engine oil after the first heat cycle of starting and running the engine. The original oil will have dissolved bearing lubricants, minute metal particles from break-in, and possibly sealant leftovers that don't need to be in the oil once we go racing. Some engine builders like to use very thin oil for the first runs so that the rings and bearings will seat faster and more efficiently.
There is not a sound more satisfying than your engine coming to life after the many hours of labor invested to properly assemble all of the components. Follow all instructions provided, don't be afraid to call the manufacturer and ask pointed questions, and by all means, take your time and pay attention to detail. Winning race motors don't necessarily have to be cheated up to outperform the competition. There's plenty to be gained from using some of these tried and true techniques.
Many teams choose to build their own engines due to convenience, budget limitations, or the simple fact that they can control what they have. There are important tips that professional engine builders have known for some time that can help make your engine build a success.